From a student-designed steel shelter set among pine trees in a Northumberland forest to the commercial might of Jean Nouvel's One New Change shopping mall in the City of London, 89 British buildings spanning the length and breadth of Britain have won a 2011 Royal Institute of British Architects award. Meanwhile 13 buildings, from the Guangzhou Opera House to the Masdar Institute in Abu Dhabi, have received RIBA international awards. While this is a case of British architects working at home and abroad giving themselves a pat on the back, the RIBA awards are one of the few opportunities to highlight some of the very best new work carried out by architects who are little known and yet whose work is often very special.

So, while you may well have heard of some of this year's award winners – Zaha Hadid for the Evelyn Grace Academy in Brixton as well as Guangzhou Opera House, Norman Foster for the Masdar Institute, Michael Hopkins for the 2012 Olympics Velodrome and Jean Nouvel for One New Change – others are not exactly household names. David Lea and Pat Borer? Peter Beard/Landroom? Sutherland Hussey?

In 2003 Sutherland Hussey, an Edinburgh-based practice whose partners have worked for James Stirling, Renzo Piano and Hadid, came to national prominence with their low-cost design for a beautiful ferry shelter on the island of Tiree; it won the Royal Incorporation of Scottish Architects award that year for the "most popular building in Scotland". Now, they have been allocated a RIBA award for Love Shack, a low-cost "eco-house" in the English Lake District with views over Lake Windermere. Happily you can rent this timber hideaway, and understand why the architects deserve the awards – and, perhaps, to be better known than they are.

This year's prizes have been won by a number of buildings that are truly sustainable and kind to the environment, both to their settings and to the wildlife that inhabits them. Any bird-lover will enjoy two special if low-key projects designed for the RSPB. These are the Marshland Discovery Zone, Purfleet by Peter Beard/Landroom and a new hide at Titchwell, Norfolk, by Haysom Ward Miller. I haven't been to the latter yet, but I do know the converted freight containers at Purfleet that have been turned into a superb bird-watching centre on the Essex marshes.

Set on piles, with sections of mesh floor, you are very aware of being out on the wilds of the marshes – the water and waterlife below you, including rare water voles, and the birdlife wheeling across the Rainham, Wennington and Aveley marshes so close to London: peregrines, avocets, lapwings, little egrets and ringed plovers among them.

In the wrong hands, and with the wrong architects, these haunting marshlands might have become acres of junk housing and other fastbuck Thames Gateway developments. The RSPB has preserved the land and been a friend to both birds and architecture. At Purfleet, you'll also find the fine RSPB shelter designed a few years ago by Van Heyningen Haward.

A school that is friendly to children, nature and teachers alike has also won a very deserving award. This is the Sandal Magna Community Primary School, Wakefield, by Sarah Wigglesworth, architect of the inspirational dance studio for Siobhan Davies that won a RIBA award in 2006, as well as the Straw House, a self-build that resembles and is partly made from a heap of bales. Another award goes this year to David Lea and Pat Borer's WISE building, Machynlleth, also known as the Wales Institute for Sustainable Education at the Centre for Alternative Technology. At the heart of this ultra-green complex is a 200-seat lecture theatre with rammed earth walls rising 7.2 metres – the tallest such structure in Britain and in every way a breath of fresh air.

Awards have also been given to the kind of big, brave (and sometimes brash) buildings that naturally grab the headlines, including the appropriately theatrical Guangzhou Opera House and Jean Nouvel's decidedly controversial One New Change in the City of London.

Now in their 46th year, the RIBA awards remain valid because they ensure that panels of local judges up and down the country get out to see buildings that might easily be overlooked. While this could never be true of an opera house by Hadid, it can all too easily be the fate of small and deliberately secret buildings such as the RSPB's hides, and forest treasures including the Shelter 55/02, created by the students of University College London.